Apparatus and method for automatic placement of transducer

Abstract

An apparatus and method is disclosed for locating a desired blood vessel within a predetermined volume of tissue. The apparatus and method includes a plurality of transducers which are operable to be positioned over the tissue. Each of the transducers when driven produces an output signal indicative of a characteristic of a blood vessel located under each transducer. A control system for selectively driving the transducers in order to produce a plurality of output signals and for comparing the plurality of output signals in order to determine the output signal having the largest amplitude which corresponds to the transducer positioned over the desired blood vessel.

What is claimed is: 
     
       1. An apparatus for locating a desired blood vessel within a predetermined volume of tissue, comprising: a plurality of transducers operable to be positioned over the volume of tissue, wherein each said transducer when driven produces an output signal indicative of a characteristic of a blood vessel located under each said transducer; and   control means for selectively driving said transducers in order to produce a plurality of output signals and for comparing said plurality of output signals in order to determine the said output signal having the largest amplitude which corresponds to said transducer positioned over the desired blood vessel.   
     
     
       2. The apparatus of claim 1, wherein said plurality of transducers are arranged in a configuration selected from a group consisting of a linear configuration and matrix configuration. 
     
     
       3. The apparatus of claim 1, wherein said plurality of transducers is a plurality of Doppler transducers including at least one flat surface. 
     
     
       4. The apparatus of claim 1, wherein the characteristic of the blood vessel is the blood flow rate. 
     
     
       5. The apparatus of claim 1, which further includes a switching network coupled between said plurality of transducers and said control means for selectively coupling each of said transducers to said control means. 
     
     
       6. The apparatus of claim 5, wherein said switching circuit is coupled to said control means by a drive line, a signal line and a control line. 
     
     
       7. The apparatus of claim 6, wherein each of said transducers are coupled to said switching circuit by an input feed and an output feed. 
     
     
       8. The apparatus of claim 6, wherein each of said transducers are coupled to said switching circuit by a single feed. 
     
     
       9. The apparatus of claim 1, wherein said switching circuit couples one of said transducers to both said drive line and said signal line in response to a select signal on said control line. 
     
     
       10. The apparatus of claim 1, wherein said control means further includes a memory device for storing said output signals. 
     
     
       11. The apparatus of claim 1, wherein said control means selectively drives said transducers in a sequential order. 
     
     
       12. The apparatus of claim 1, wherein said control means first selectively drives said transducers by first dividing said transducers into a predetermined number of sections and then sequentially driving each of said sections of transducers at a time until a desired section of transducers is chosen having output signals with the greatest amplitude and then said control means selectively drives said desired section of transducers by continually dividing said desired section of transducers into groups of halves and then sequentially driving each of said halves. 
     
     
       13. A method for locating a desired blood vessel within a predetermined scanning area of skin tissue, said method comprising the steps of: positioning a plurality of transducers over the scanning area;   selectively driving said transducers in order to produce a plurality of output signals which are indicative of a characteristic of blood vessel located adjacently to said transducers; and   comparing said plurality of output signals in order to determine said output signal having the largest amplitude which corresponds to said transducer positioned adjacent to the desired blood vessel.   
     
     
       14. The method of claim 13, which further includes driving said transducer positioned adjacent to the desired blood vessel after said comparing step in order to determine said characteristic of desired blood vessel. 
     
     
       15. The method of claim 13, wherein said selectively driving of said transducers is performed in a sequential order. 
     
     
       16. The method of claim 13, wherein said selectively driving of said transducers is performed by sequentially driving a quarter of said transducers at a time until said quarter of said transducers is chosen having output signals with the greatest amplitude. 
     
     
       17. The method of claim 13, wherein said selectively driving of said transducers is performed by continually dividing said transducers into groups of halves and then sequentially driving each of said halves. 
     
     
       18. The method of claim 13, wherein the characteristic of the blood vessel is the blood flow rate. 
     
     
       19. The method of claim 13, wherein said plurality of transducers are arranged in a configuration selected from a group consisting of a linear configuration and matrix configuration. 
     
     
       20. The method of claim 13, wherein said plurality of transducers is a plurality of Doppler transducers including at least one flat surface. 
     
     
       21. An apparatus for locating a desired blood vessel within a predetermined volume of tissue, comprising: a plurality of transducers operable to be positioned over the volume of tissue, wherein each said transducer when driven produces an output signal indicative of a characteristic of a blood vessel located under each said transducer; and   control means for selectively driving said transducers in order to produce a plurality of output signals and for comparing said plurality of output signals in order to determine the said output signal having the largest amplitude which corresponds to said transducer positioned over the desired blood vessel, wherein said control means selectively drives said transducers by continually dividing said transducers into groups of halves and then sequentially driving each of said halves.